Ex Quiz Ex Quiz Practice QuestionsWill turn Green if correct, Red if incorrect.Full summary at end of quiz.80 Questions in total. 1 / 80 Which one of the following letters, when used as a certification number suffix, indicates that apparatus has 'Component certification' X C U B 2 / 80 Apparatus marked in accordance with ATEX 95 will be designed to provide a specific 'level of protection' for the zone of use and indicated by an 'equipment category'. Which one of the following categories indicates apparatus is suitable for use in zone 0 in a chemical plant. M1 M2 1 2 3 / 80 If not marked on the certification label, It can be assumed that the ambient rating of the apparatus for use in the UK is: 50°c 45°c 40°c 35°c 4 / 80 Apparatus manufactured to BS EN60079 standards requiring attention to Special installation conditions' will be indicated by which of the following suffixes? B X S U 5 / 80 The recommendations for the installation of electrical system in hazardous areas are provided by which one of the following standards? BS EN50017 BS EN6009-17 BS EN50014 BS EN60079-14 6 / 80 Apparatus marked [Ex ia] what does this mean? It is intrinsically safe apparatus that can be installed anywhere Always refer to documentation It's a piece of 'ia' equipment inside another enclosure The equipment is associated with circuits that are intrinsically safe 7 / 80 The -rating, e.g. T5 marked on he certification label of equipment indicates that the surface temperature of the equipment? Will not reach the flashpoint temperature of the gas in normal operation Is designed to reach the temperature represented by the T-rating Will not reach the ignition temperature of any dust or gas n normal operation Will not exceed the temperature represented by the T-rating during normal or specified fault conditions 8 / 80 The numbers after the letters IP in the ingress protection codes represent? Solid particles and mechanical protection Supply voltage and water pressure Solid particles and water Dust particle size and condensation 9 / 80 The property of a flammable material which is considered in order to determine the appropriate T-rating for equipment is? The upper flammable limit of the material The material sub-division The ignition temperature of the material The flash point of the material 10 / 80 Which one of the following statements represents the presence of a flammable mixture in zone 0 Not likely to occur Not present during normal operation Present continuously, or for long periods, or frequently Present in normal operation occasionally 11 / 80 Spontaneous ignition of a flammable mixture occurs at? Its fire point Its upper ignition temperature Its flash point Its ignition temperature 12 / 80 Fitting new (metric thread) cable glands to older flameroof equipment, with imperial thread forms at the cable gland entries, this may be achieved by? Re-tapping the entries using a metric tap the same size as the gland Using an Exd or Exde adaptor with appropriate thread forms Fitting threaded inserts after drilling Fitting the metric gland as far s possible with the aim of achieving five-full threads engagement 13 / 80 Obstruction of the flamepath openings of the flanged joints of Ex d enclosures by solid obstructions requires minimum clearances depending on the equipment gas group. For a IIC enclosure this is not less than? 30mm 40mm 10mm 50mm 14 / 80 Maximum gaps and minimum widths are specified for the joints of flameproof enclosures in order to? Cool the hot gases / products of an internal explosion Improve the mechanical strength of the enclosure Allow a gasket to be fitted Relieve the pressure of an internal explosion 15 / 80 Which one of the following may be applied in the gap of a flameproof flanged joint to improve the IP rating? Thermosetting sealant Non setting grease Non-hardening grease bearing textile tape Any oil based paint 16 / 80 Cable glands entering flameproof enclosures are required to achieve a minimum number of threads engagement. The minimum requirement is? Eight full threads Ten full threads Three full threads Five full threads 17 / 80 If a zone 1 area on an rea classification diagram is marked s requiring EPL 'Ga' equipment by a risk assessment, this is due to: ? The EPL is wrongly specified on the diagram A higher that normal risk of ignition A lower than normal risk of ignition The consequences of ignition are higher than normal 18 / 80 Which of the following types of pressurised enclosures, containing a source of ignition, may be used in an area requiring EPL 'Gc' equipment Ex 'px' or Ex 'pz' Protection not required 'py' 'px' 19 / 80 For which one of the following apparatus sub-groups is ethylene the representative gas? I IIA IIB IIC 20 / 80 Cable gland for entry to flameproof enclosures are required to have a minimum number of threads engaged and thread depth, the purpose being to? Prevent flammable gases entering the enclosure Preserve the strength of the enclosure Preserve the enclosure IP rating Prevent the effects of an internal ignition transmitting to and igniting an external flammable gas 21 / 80 Pressure piling in a flameproof enclosure may be described as? Metal fatigue due to excessive stresses Operation of a vent due to gas pressure Piles for supporting heavy equipment Ignition in one section of an enclosure causing a stronger secondary explosion in another connected section 22 / 80 The minimum IP rating for 'Ex e' equipment is? IP64 IP6X IP44 IP54 23 / 80 Which one of the following descriptions represents equipment marked 'Ex e'? Intrinsically safe Increased safety Flameproof Enhanced safety 24 / 80 Which one of the following locations may 'Ex n' equipment be installed? EPL Gb (Cat 2G) locations only EPL Gc (Cat 3G) locations only EPL Ga (Cat 1G) locations EPL's Gb & Gc (Cats 2G & 3G) locations 25 / 80 Four variations of 'Ex n' equipment are available, which are? Na, Ne, NL & Nr na, nB, nC & nD no, nA, nC, nR nA, nC, nL, & nR - 26 / 80 Installed in 2009, an 'Ex d' motor has an 'Ex e' terminal box. Which one of the following gland options may be used on a SWA cable? Uncertified El W Exi Ex d Ex d or Ex e 27 / 80 A steel 'Ex e' enclosure has a threaded entry 10mm in length. Which one of the following options achieves the minimum installation requirement when fitting an Ex e E1W cable gland? Fit gland Fit gland, external IP washer and internal serrated washer Fit gland, external IP washer and internal lock nut Fit gland, earth tag, serrated washer and internal lock nut 28 / 80 For 'Ex e' equipment installed in 2005, which one of the following glands is not acceptable? E1W Ex e certified E1W uncertified E1WF Ex d certified Uncertified plastic A2 29 / 80 The tE time of an Ex e motor indicates? The run-up time to full speed The disconnection time for a stalled motor after starting from hot The disconnection time for a stalled motor operating at its normal running temperature The minimum time interval between re-starts 30 / 80 The requirements for cable glands entering 'Ex n' equipment after 2007 are? 'Ex d' barrier gland 'Ex e' certified gland Certified as meeting the requirements of IEC60079-0 'Ex d' certified gland 31 / 80 An 'Ex de' motor, with an 'Ex e' terminal box, was installed in 2005. Which one of the following cable glands achieves the minimum installation requirements? An E1W Ex e gland An E1WF Ex d gland An uncertified gland which meets the IP and impact requirements An Ex d gland 32 / 80 A steel 'Ex e' enclosure has clearance entries. What is the minimum requirement for installing an SWA cable? Fit gland, internal IP washer, serrated washer and locknut Fit gland, earth tag, serrated washer and internal locknut Fit gland, external IP washer, internal serrated washer and locknut Fit gland, external IP washer, internal locknut and shroud 33 / 80 Which one of the following restrictions apply to 'Ex e' & 'Ex n' light fittings? Lamps using non-conducting end-caps or pins with a conductive coating are prohibited unless tested with the equipment Lamps using conducting end-caps or pins are prohibited Lamps with screwed connections are prohibited Fluorescent lamps must be bi-pin 34 / 80 An increased safety enclosure is marked Ex e II T6. The absence of a letter after 'Il' indicates the enclosure may be used in: Group IIC gases only Group IIA gases only All gas groups Incombustible dusts only 35 / 80 The purpose of seals at the joints of 'Ex e' enclosures is to Prevent the ingress of solids and moisture Prevent the ingress of flammable gases/vapours Insulate the parts from one another Contain an internal explosion 36 / 80 The minimum cross-sectional area for aluminium conductors of cables (except I.S. cables) used in hazardous areas should not be less than? 25mm 16mm 10mm 6mm 37 / 80 The installation of equipment in hazardous locations essentially requires an understanding of which one of the following? Combustion engine operation Preparation of area classification diagrams Protection types Process instrumentation 38 / 80 Separation of the strands of cable cores may be prevented by? Soldering or fitting core lugs Twisting the strands Fitting cable lugs or core-end sleeves Soldering the strands 39 / 80 A cable gland marked with a suffix 'X' may only be used with? Portable equipment with additional clamping of the cable Fixed equipment with additional clamping of the cable An enclosure also marked with a suffix 'X' Fixed equipment 40 / 80 Which one of the following statements, given in BS EN60079-14, represents the knowledge and skills required by technicians for the selection and erection of equipment? Quality assurance Detailed knowledge of the relevant techniques Familiarity with the relevant techniques Detailed knowledge of the principles employed 41 / 80 Cables for non-intrinsically fixed equipment are required to be thermoplastic, thermosetting or elastomeric provided they are? Circular, compact, have extruded bedding and fillers Flat, compact, with extruded bedding and fillers Circular, compact, with extruded bedding & fillers are non-conductive Circular, compact, have extruded bedding, and fillers, if any, are non-hygroscopic 42 / 80 The limitation for installation materials, such as cable tray, in an area requiring EPL Gc rated equipment is? No limitations Contains no more than 7.5% aluminium Contains no more than 7.5% aluminium and titanium Contains no more than 7.5% aluminium, titanium and zirconium 43 / 80 An enclosure is marked EEx d IIC, is direct entry and has a free internal volume of 1 litre and is installed in an area requiring EPL Gb (Cat 2G) equipment. What is the minimum acceptable cable gland if round compact SWA cable with extruded bedding are used? Certified E1WF, Ex d IIC barrier gland Certified E1WF, Ex e cable gland Uncertified E1W cable gland Certified E1WF, Ex d IIC cable gland 44 / 80 Unused cable cores of multi-cored cables are required to be terminated by which one of the following? Terminate in unearthed terminals Cut back and insulate both ends with tape Connect one end to the neutral conductor Connect both ends to earth 45 / 80 Which one of the following statements represents the assessment requirements for technicians as given in BS EN60079-14? A degree in Electrical Engineering Evidence only of having the necessary skills for the scope of work Evidence only of having the necessary skills for the scope of work and competence across the range activities Evidence indicating the necessary skills for the scope of work, competence across the range of activities and relevant knowledge and understanding 46 / 80 Which one of the following values, as given in BS EN60079-14, is the limit for the insulation resistance of plastic cable tray in order to avoid static electricity? Greater than 1MΩ Greater than 1GΩ Not exceeding 1GΩ Not exceeding 1MΩ 47 / 80 Before work is carried out in a hazardous location which one of the following is necessary to understand? The manufacturer's documentation The basic requirements for working in the zones of hazardous areas Circuit diagrams for panel wiring How the equipment operates 48 / 80 The reduction of static electricity on new plastic cable tray may be reduced by which one of the following? Limiting the cable tray length Limiting the cable tray surface area Using braided armour cables Installing I.S. circuits only on the cable tray 49 / 80 Which one of the following locations may Ex ic equipment be used? EPL Gc (Cat 3G) only EPL's Gb & Gc (Cat 2G & Cat 3G) EPL Ga (Cat 1G) EPL's Ga, Gb & Gc (Cat 1G, Cat 2G & Cat 3G) 50 / 80 The comparison between Ex nL and Ex ic is correctly stated by which one of the following statements? Both may be used in zones 0, 1, and 2 Both may be used in zone 2 only Ex nL may be used in zones 0, 1 & 2 and Ex nL in zone 2 only Ex ic can be installed in zones 0, 1&2 but Ex nL in zone 2 only 51 / 80 The maximum resistance of the cables connecting a zener barrier earth bar and the main earth should not exceed? 1Ω 10Ω 1MΩ 100Ω 52 / 80 Which one of the following colours is recommended for the identification of I.S. cables? White Yellow Light Blue Red 53 / 80 The minimum cross-sectional area of a single I.S. earth conductor is? 2 x 4.0 mm 2 x 6.0 mm 1 x 4.0 mm 2 x 2.5 mm 54 / 80 The equipment in the hazardous area which may be connected to the output of a zener barrier is which one of the following? Fireproof equipment only The apparatus specified in the documentation only Any equipment Any I.S. certified equipment and simple apparatus 55 / 80 Which one of the following statements indicates the correct requirements for an installation comprising both IS and non-IS circuits? IS and non-IS cables may be installed side-by-side IS and non-IS cables must be run on separate cable trays Non-IS cables must always be screened, armoured or metal sheathed Either the IS or non-IS cables need only be armoured, screened or metal sheathed 56 / 80 The minimum clearance between different adjacent I.S. circuits is? 50mm 3mm 5mm 6mm 57 / 80 The maximum permitted supply voltage (Um) at the non-IS terminals of an IS installation is? 250V 28V As specified in the documentation 115V 58 / 80 An appropriate workshop test for a faulty zener barrier with a possible blown fuse would be? Disconnect output and measure voltage Disconnect and measure resistance between output terminals Place barrier in a test rack and measure the current Disconnect and measure the resistance between the barrier input and output terminals 59 / 80 From the following statements, which one has equipment that does not require a dedicated I.S. earth? Barrier used in circuit installed in group IIC gases Zener barrier with output connected in hazardous area 24V zener barrier Galvanic isolation barrier 60 / 80 What does the marking, [Ex ib] IIC, on an item of IS equipment indicate? It is intrinsically safe and for use with IIC gases It is intrinsically safe and can be installed anywhere It is associated with circuits which are intrinsically safe It can be installed in a Zone 0, Ga location 61 / 80 The minimum clearance between I.S. terminals and earth is? 30mm 50mm 3mm 6mm 62 / 80 The screen of a cable in an I.S. circuit must be connected to? The main earth conductor The point indicated on the loop (hook up) diagram Earth at both ends Earth at one end only 63 / 80 Equipment marked Ex d [ia] indicates that? The flameproof enclosure is deemed 'simple apparatus' in an 'ia' circuit The flameproof enclosure contains associated I.S. equipment The components inside are all intrinsically safe Electrical items other than I.S. items are inside 64 / 80 I.S. cables with screens will have sheathing capable of withstanding which one of the following test voltages? 500Vac and 750Vdc 500Vac or 750Vdc 1000V Double the working voltage 65 / 80 Which one of the following components may be considered simple apparatus for use in an I.S. circuit? 0.1kW motor An L.E.D. A 9V battery An electronic relay 66 / 80 The purpose of a zener barrier in an I.S. circuit is to? permit the use of any certified equipment in the hazardous area Control the capacitance and inductance levels in the hazardous area permit the use of both simple and certified apparatus in the hazardous area limit the level of energy that may pass into the hazardous area equipment 67 / 80 Equipment with an I.S. output is installed in a flameproof enclosure. Which one of the following cable glands should be used for the I.S. output cable? A standard industrial cable gland An Ex e certified cable gland A flameproof Ex d certified cable gland An Ex i cable gland 68 / 80 The letters used to indicate the different EPL levels of explosion protected equipment are? x, y & z a, b & c u, v & w A, B & C 69 / 80 Which of the following EPL's marked on explosion protected equipment may be used in Zone O? Ga, Gb & Gc Gc only Ga only Gb only 70 / 80 The recommendations for the inspection of electrical systems in hazardous areas are given in which one of the following standards? BS EN50017 BS EN60079-17 BS EN50014 BS EN60079-14 71 / 80 EPL is the Internationally recognised abbreviation for? Explosion protection level Enclosure protection level Equipment protection level Equipment protection limit 72 / 80 Which one of the following is not required for combustion of a flammable material? Oxygen An enclosure An ignition source Fuel 73 / 80 The number of temperature classes for marking explosion protected equipment is? 8 4 6 5 74 / 80 An area classification diagram will represent zone 1 by which one of the following? Cross-hatching at 45 degrees Small circles Lines angled at 45 degrees As indicated by drawing key 75 / 80 Equipment marked T6 will have a maximum surface temperature of? 450°C 300°C 85°C 100°C 76 / 80 Which one of the following sub-divisions is necessary for equipment in an acetylene hazard? IID IIC IIB IIA 77 / 80 Where CLOSE inspections are carried out on an Ex pz High Voltage motor, which of the following checks are required? Check that ducts pipes and enclosures are in good condition Measure the IR of the Stator winding Check that the electrical protective devices operate within permitted limits Check that the electrical protective devices are set correctly 78 / 80 Pressure piling in a flameproof enclosure is caused by? Over-current protection set too high Exceeding the equipment rated voltage Excessive tightening of cover bolts Alteration of the internal component layout 79 / 80 When an enclosure is termed 'flameproof' it indicates that? An explosion will not dislodge it from its fixings It will not burn It will operate continuously in a fire Gas around the enclosure will not be ignited by an internal explosion 80 / 80 The minimum requirement for tightening the cover bolts of a flameproof enclosure to ensure its safe operation is? All cover bolts fitted but only alternate bolts need be spanner tight Some bolts missing (up to 20%) and the rest spanner tight All cover bolts fitted and spanner tight All cover bolts fitted and tightened by torque wrench in excess of 60kgfm Your score isThe average score is 69% 0% Restart quiz
